# US 11,122,693 B2 · Method for forming laminated circuit board

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- Number: US 11,122,693 B2
- Document ID: US11122693B2
- Status: Granted
- Kind: B2
- Application number: 15/676,472
- Filed: 2017-08-14
- Published: 2017-12-28
- Granted: 2021-09-14
- Earliest claimed: 2015-02-13
- Assignees: Pi-Crystal Incorporation
- Applicants: Pi-Crystal Incorporation
- Inventors: Junichi Takeya; Seiichiro Yamaguchi; Masataka Itoh
- Web page: https://patentgrep.com/patent/US11122693B2

## CPC

- H05K 3/361: {Assembling flexible printed circuits with other printed circuits}
- H05K 1/115: {Via connections; Lands around holes or via connections (H05K1/112 takes precedence)}
- H05K 1/116: {Lands, clearance holes or other lay-out details concerning the surrounding of a via}
- H05K 1/118: {specially for flexible printed circuits, e.g. using folded portions}
- H05K 1/144: {Stacked arrangements of planar printed circuit boards}
- H05K 3/363: {by soldering}
- H05K 3/403: {Edge contacts; Windows or holes in the substrate having plural connections on the walls thereof (H05K3/4092 takes precedence)}
- H05K 3/4038: {Through-connections; Vertical interconnect access [VIA] connections (H05K3/403, H05K3/42 take precedence)}
- H05K 3/4623: {the circuit boards having internal via connections between two or more circuit layers before lamination, e.g. double-sided circuit boards (H05K3/462 takes precedence)}
- H05K 3/4635: {laminating flexible circuit boards using additional insulating adhesive materials between the boards}
- H05K 3/4691: {Rigid-flexible multilayer circuits comprising rigid and flexible layers, e.g. having in the bending regions only flexible layers}
- H05K 1/028: {Bending or folding regions of flexible printed circuits (H05K1/0283 takes precedence)}
- H05K 1/0393: {Flexible materials (H05K1/038 takes precedence; specific organic compositions are classified in H05K1/0313 and subgroups)}
- H05K 3/1275: {by other printing techniques, e.g. letterpress printing, intaglio printing, lithographic printing, offset printing}
- H05K 2201/041: Stacked PCBs, i.e. having neither an empty space nor mounted components in between
- H05K 2201/058: Direct connection between two or more FPCs or between flexible parts of rigid PCBs
- H05K 2201/09181: Notches in edge pads
- H05K 2201/09845: Stepped hole, via, edge, bump or conductor
- H05K 2201/10121: Optical component, e.g. opto-electronic component
- H05K 2201/10151: Sensor
- H10W 72/072: {of bump connectors}
- H10W 99/00: Subject matter not provided for in other groups of this subclass
- Y10T 29/49124: On flat or curved insulated base, e.g., printed circuit, etc.
- Y10T 29/49126: Assembling bases
- H05K: PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Described are processes for developing laminated circuit boards, as well as the resulting circuit boards themselves. Accordingly, at least two circuit boards at least partially overlap each other, and at least one through-hole is formed in an overlapping region thereof. The through-hole is filled with an electrically-conductive material, forming a through-via that enables the circuit boards to be electrically connected. When a circuit on each circuit board is laid out so that a part thereof reaches a region in which the through-via is to be formed, then that part of the circuit can be electrically connected to the through-via. Thus, portions of the circuits on the circuit boards can be electrically connected to each other via common through-vias to realize an integrated device in which the circuits on the laminated circuit boards function.

## Claims

### Claim 1

A method for forming a laminated circuit board in which a plurality of flexible circuit boards are laminated, each flexible circuit board being provided with a printable electronic device that is formed on a flexible film using a printing technique, wherein
an organic semiconductor circuit is formed on at least one of the plurality of flexible circuit boards,
the plurality of flexible circuit boards each have at least one side surface and are arranged so that a region in a vicinity of the one side surface of one flexible circuit board among the plurality of flexible circuit boards overlaps a region in a vicinity of the one side surface of at least one other of the plurality of flexible circuit boards,
wherein each of the plurality of flexible circuit boards has a top side and a bottom side, and an area of the bottom side of two of the flexible circuit boards is less than an area of the top side of the at least one other flexible circuit board, and
electrical connection of the one flexible circuit board with the at least one other flexible circuit board is made via a through-via that is formed in a vicinity of one edge of the one flexible circuit board and a region in a vicinity of the one edge of the at least one other flexible circuit board, or via an electrically-conductive material arranged on the one side surface of the flexible circuit boards.

### Claim 2 (depends on 1)

The method for forming a laminated circuit board according to claim 1, wherein the electrical connection is made by forming at least one through-hole that penetrates the plurality of flexible circuit boards in the vicinity of the one edge of the one flexible circuit board and the region in the vicinity of the one edge of the at least one other flexible circuit board in a state in which the one flexible circuit board and the at least one other flexible circuit board overlap each other, embedding the electrically-conductive material in the through-hole to form the through-via, and laying out in advance circuit interconnects on the circuit boards so that parts of the circuit interconnects reach the vicinity of the one edge of the one flexible circuit board and the region in the vicinity of the one edge of the at least one other flexible circuit board in which the through-via is to be formed.

### Claim 3 (depends on 2)

The method for forming a laminated circuit board according to claim 2, wherein an opening of the through-via increases toward a top layer.

### Claim 4 (depends on 1)

The method for forming a laminated circuit board according to claim 1, wherein the electrical connection is made by forming a through-hole of the through-via in advance in a process of forming the one flexible circuit board and the at least one other flexible circuit board, embedding the electrically-conductive material in the through-hole in a state in which the one flexible circuit board and the at least one other flexible circuit board overlap each other to form the through-via, and laying out in advance circuit interconnects on the one flexible circuit board and the at least one other circuit board so that parts of the circuit interconnects reach the regions in which the through-via is to be formed.

### Claim 5 (depends on 4)

The method for forming a laminated circuit board according to claim 4, wherein an opening of the through-via that is formed in the plurality of laminated circuit boards increases toward a top layer.

### Claim 6 (depends on 1)

The method for forming a laminated circuit board according to claim 1, wherein the plurality of flexible circuit boards are classified into two or more groups, a flexible circuit board lamination in which a plurality of flexible circuit boards are laminated is formed for each group, and the plurality of flexible circuit board laminations are laminated.

### Claim 7 (depends on 1)

The method for forming a laminated circuit board according to claim 1, wherein the electrical connection is made by forming a notch-shaped or semicircular recess in an end face of each of the flexible circuit boards, and arranging the electrically conductive material along the notch-shaped or semicircular recess to bring the electrically conductive material into contact with circuit interconnects formed on the flexible circuit boards.